As the hitherto known organic photoconductive compounds, there are both polymeric or non-polymeric photoconductive compounds. Examples of said polymeric organic photoconductive compounds among them include poly-N-vinylcarbazole, poly-N-vinylcarbazole derivatives, polyacenaphthylene and the like, and examples of said non-polymeric organic photoconductive compounds include various aromatic condensates, heterocyclic compounds, aromatic amines, such as, for example, anthracene, imidazolone derivatives, oxazole derivative, N,N,N',N'-tetraphenyl-p-phenylenediamine derivative, benzidine derivative and the like. The former may usually be applied directly or in a mixture with a desirable plasticizer, and the latter in a mixture with a desirable binder to a support to make a uniform and smooth, glassy sensitive layer.
It has been generally known that the incorporation of various kinds of dyes into the photoconductive compound layer, in the case where the photoconductive compound is sensitive to ultraviolet rays, induces a spectral sensitization and can give a sensitive layer having a sensitivity at a visible region, and that the addition of an electron accepting compound, in the case where the photoconductive compound used shows an electron donating property, converts to an electron transfer type compound and leads to its chemical sensitization.
Thus, for example, as spectrum sensitizers there are known dyes, such as, rhodamine B, rhodamine B extra, crystal violet, victoria blue-B, fuchsine, night blue and acridine orange, and pyrylium salt. And also as the chemical sensitizer, there are known quinones, such as, anthraquinone, 2-methylanthraquinone, 1-nitroanthraquinone, and tetracyanoethylene, tetracyanoquinodimethane, benzoic acid, p-chlorophenol, m-nitrophenol, cinnamic acid and the like.
An object of the present invention is to obtain a chemical sensitizer showing far more excellent sensitizing effect than that of the hitherto known ones in the field of the latter chemical sensitizers, and another object of the present invention is to obtain an organic photoconductive composition sensitized with said sensitizer.